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This article addresses broad trends in interdisciplinary research in physics where interactions with colleagues in fields such as computer science, ecology, or economics can often be derailed by unintentional clashes of methodologies and perspectives on the core science. Key causes of such breakdowns in interdisciplinary work are detailed and solutions offered.
A brief survey is made to highlight the recent interests in positron, positronium and antimatter physics. Positron is the first antiparticle observed which was predicted by Dirac. Positronium is itself its antiparticle and bi-positronium molecule is recently observed in laboratory which was predicted by Wheeler. The simplest antiatom i.e. antihydrogen is observed in the laboratory and the process to achieve the stable confinement of antihydrogen within the trap are in progress to test the standard model.
Remarks on Michael Frayn's play "Copenhagen".
The limitations of current technology do not allow one to foresee the expansion of the humankind beyond our planet for at least a few decades. Furthermore, the laws of physics, as for as they are known, preclude any form of traveling beyond the speed of light, as well as any viable and stable space-time shortcuts (wormholes, warp-drives, etc) that would facilitate cosmic traveling. Given the vastness of the Universe these are insurmountable obstacles for any {\it in situ} exploration of the cosmos beyond our most immediate cosmic neighbourhood. Nevertheless, the Universe is transparent and contains countless sources of visible light. Actually, in the last decades, technological developments have made possible to observe the cosmos throughout most of the electromagnetic spectrum as well as to perform dynamical studies that allow perceiving the presence of invisible components such as black holes, dark matter and dark energy. In this respect, humankind has then been given the opportunity to unravel the inner workings of the cosmos and through this process be part of the cosmic habitat. In this contribution various forms of cosmological thinking will be discussed, from some myths of creation till some of the latest scientific discoveries.
One of the big problems of the age concerns 'Global Warming', and whether it is 'man-made' or 'natural'. Most climatologists believe that it is very likely to be the former but some scientists (mostly non-climatologists) subscribe to the latter. Unsurprisingly, the population at large is often confused and and is not convinced either way. Here we try to explain the principles of man-made global warming in a simple way. Our purpose is to try to understand the story which the climatologists are telling us through their rather complicated general circulation models. Although the effects in detail are best left to the climatologists' models, we show that for the Globe as a whole the effects of man-made global warming can be demonstrated in a simple way. The simple model of only the direct heating from the absorption of infrared radiation, illustrates the main principles of the science involved. The predicted temperature increase due to the increase of greenhouse gases in the atmosphere over the last century describes reasonably well at least most of the observed temperature increase.
I discuss Gisin's result showing that sets of quantum-correlated spacelike events cannot be described by a covariant probability distribution over hidden variables, and his conclusion that Tumulka's "rGRWf" (relativistic GRW "flash ontology" model) is an appropriate model to resolve the apparent conflict between quantum theory and relativity. The contrasts and similarities between the Transactional Interpretation's (TI) handling of a specific measurement result and that of GRW approaches are clarified. I argue that TI resolves the apparent conflict between quantum theory and relativity described by Gisin in a harmonious manner, without the necessity of modifying the theory.
In this paper, a different perspective of constructing the CA models is proposed. Its kernel, the Local Symmetric Distribution Principle, relates to some fundamental concepts in physics, which maybe raise a wide interest. With a rich palette of configurations, this model also hints its capability of universal computation.
We discuss the motivation for pursuing research on the foundations of quantum theory.
We introduce the `Complete Wave Function' and deduce that all living beings, not just Schroedinger's cat, are actually described by a superposition of `alive' and `dead' quantum states; otherwise they would never die. Therefore this proposal provides a quantum mechanical explanation to the world-wide observation that we all pass away. Next we consider the Measurement problem in the framework of M-theory. For this purpose, together with Schroedinger's cat we also place inside the box Rasputin's cat, which is unaffected by poison. We analyse the system identifying its excitations (catons and catinos) and we discuss its evolution: either to a classical fight or to a quantum entanglement. We also propose the $BSVΨ$ scenario, which implements the Complete Wave Function as well as the Big Bang and the String Landscape in a very (super)natural way. Then we test the gravitational decoherence of the entangled system applying an experimental setting due to Galileo. We also discuss the Information Loss paradox. For this purpose we consider a massless black cat falling inside a massive black hole. After that we outline a method to compute the contribution of black cats to the dark matter of the universe. Finally, in the spirit of Schroedinger, we propose that next generation double-slit experiments should use cats as projectiles. Cat interferometry will inevitably lead to the `Many Cats' interpretation of Quantum Mechanics, allowing to shed new light on old mysteries and paradoxes. For example, according to this interpretation, conservative estimates show that decision making of a single domestic cat will create about 550 billion whole universes every day, with as many replicas of itself.
The enormous pressure lifting the column of oil in a leaking oil well can thwart efforts to seal the top of the well and prevent oil from rising. When the oil cannot be stopped completely, we propose to slow its flow by filling the well with a porous medium. That medium consists of countless small, dense, streamlined objects that are dropped into the well and descend through the rising oil at terminal velocity. The resulting heap of objects couples to the oil via viscous and drag forces, dissipating the oil's energy and upward momentum and significantly reducing its rate of flow.
This paper investigates the motion of falling leaves through modeling using papers and the corresponding data collected from more than four thousands experiments. Two series of experiments were designed in order to study the relationship between different parameters which can affect different paths of motion in leaves. In the first series of experiments, the shapes of the potential paths that falling papers can take were investigated as a whole. A new classification scheme was derived from these experiments, categorizing the motion of falling sheets of paper based on the deviation from the original point of release and the shape of the path they take on their descending journey. We believe this new classification scheme can be very useful with potential applications in various fields such as biology, meteorology, etc.; it can also build a foundation for further experiments. The second set of experiments was focused on the dynamics and shape of the motion of the falling paper itself. It was observed from these experiments that there should be two critical values for Froude number in the falling paper motion in regards to the rotational motion. We also found that the most stable and dominant rotational motions are those observed around the length axis as well as the ones along the diagonal axis.
The Fermi Paradox is the apparent contradiction between the high probability extraterrestrial civilizations' existence and the lack of contact with such civilizations. In general, solutions to Fermi's paradox come down to either estimation of Drake equation parameters i.e. our guesses about the potential number of extraterrestrial civilizations or simulation of civilizations development in the universe. We consider a new type of cellular automata, that allows to analyze Fermi paradox. We introduce bonus stimulation model (BS-model) of development in cellular space (Universe) of objects (Civilizations). When civilizations get in touch they stimulate development each other, increasing their life time. We discovered nonlinear threshold behaviour of total volume of civilizations in universe and on the basis of our model we built analogue of Drake equation.
Icicles form when cool water drips from an overhanging support under ambient conditions which are below freezing. Ice growth is controlled by the removal of latent heat, which is transferred into the surrounding air via a thin film of water flowing over the ice surface. We describe laboratory experiments in which icicles were grown under controlled conditions. We used image analysis to probe the evolution of the icicle shape under various conditions. A recent asymptotic theory suggests that, overall, icicles converge to self-similar shapes which are predicted to be attractors. On the other hand, stability theory predicts that the ice-water interface can become unstable to form ripple patterns on the icicle surface. Our experimental results show that the predicted self-similar profile is only found in certain cases, and that icicles can also exhibit unpredicted non-uniformities such as branching near the tip. We find that pure water icicles are more likely to be self-similar than those grown from tap water. Ripples, which are also deviations from the self-similar profile, were observed to climb upward during icicle growth.
Many hoards found in Ireland, Scotland, Orkney Islands, and Scandinavia demonstrate the vikings ability to fabricate beautiful arm and neck rings of twisted silver and gold rods. Characteristic for such rings is the uniform appearance of the twisted pattern along the length of the arm ring, as well as from one arm ring to another, also when found at distant geographical locations. How can the appearance of the twisted wires be so perfectly repetitive? We demonstrate that the answer is that the vikings utilized a self-forming motif: The pattern arises from a twisting of the wires to a maximally rotated configuration. That is why the twist patterns in these arm and neck rings are beautiful, repetitive, and universal.
A priority of physics instruction is to help students make the connection between the formulae they think they are required to memorize and the real world in which they interact every day. If you ask students to describe a situation in real life involving physical principles, the most commonly cited examples will pertain to vehicular motion. One situation in real life involving physical principles is vehicle dynamics. Even students who have little interest in physics eagerly discuss problems like how much a car can decelerate travelling in a flat turn or how tricks like the Wheely can be performed on a motorcycle. In the physics classroom, the motion of automotive vehicles is probably the most interesting manifestation of the principles of physics. The laws of physics limiting movements of vehicles are deduced here in a simple derivation suited for classroom demonstration as well as for homework. Due to limits on frictional forces there are subsequent limits for acceleration, deceleration and speed in a flat turn. Frictional forces also determine the behaviour of a vehicle at rapid speed in a turn.
It has been suggested that consciousness plays an important role in quantum mechanics as it is necessary for the collapse of wave function during the measurement. Furthermore, this idea has spawned a symmetrical proposal: a possibility that quantum mechanics explains the emergence of consciousness in the brain. Here we formulated several predictions that follow from this hypothetical relationship and that can be empirically tested. Some of the experimental results that are already available suggest falsification of the first hypothesis. Thus, the suggested link between human consciousness and collapse of wave function does not seem viable. We discuss the constraints implied by the existing evidence on the role that the human observer may play for quantum mechanics and the role that quantum mechanics may play in the observer's consciousness.
We analyse the classical problem of the stability of bicycles when moving quickly and upright. Developing a lean causes the front wheel to turn thereby setting the bicycle instantaneously into circular motion. The centripetal force associated with the lean-dependent turning circle gives a restoring torque which corrects the lean. The force also helps self-steer the front wheel, ensuring the bicycle continues in an essentially straight path. We give the frequency of lean oscillations about the vertical executed during riding. As in the literature, we discuss the neglect of gyroscopic effects, which experiment suggests are negligible.
In this brief article I describe an experiment to illustrate how a fuse works. I have used this as part of lessons for my year 11 classes to demonstrate how an electrical fuse 'blows' when too high a current passes through it.